ios – iPhone app runs on iPhone 4 size with black bars after update

Earlier, the app supported the iPhone 5s / SE screen and the iPhone 6-8 screens (not plus sizes), this was done using launch pictures. So on Plus devices and iPhone X * devices, it would show black bars above and below the app.

We released an update where, among other things, a launch storyboard was added. Through the development of this update, the screen size worked perfectly on all devices we had. However, after deleting the update on the App Store, for some users, the app now shows the iPhone 4 size (aspect ratio is 1.5). So now affected users on an SE have the black lines, and X * users have bigger black bars before. This does not seem to affect everyone, and we cannot replicate on our devices.

The deployment target is 1

0, so there should be no reason to use the old launch image method. And the update is definitely using a storyboard for the launch screens.

Has a similar thing happened to anyone else? Or is it something you have to do especially when releasing an update that moves to the storyboard method from individual launch images?

All existing answers say either to make sure you have the right screens, or use a xib / storyboard. We have no screenshots and definitely use a storyboard.

EDIT: Now after a few hours of starting the app, users are starting to see the right sizes, which means it's an iOS caching problem.